The simulation of electric equipment using a magnetic material, such as a motor and a power generator, is widely performed in various scenes by the improvement in performance of a computer and the progress of a method for analyzing an electromagnetic field. A difference method and a finite element method are generally used as the method for analyzing the electromagnetic field. In recent years, the efficiency of the electric equipment is emphasized greatly as an approach to CO2 reduction or prevention of global warming, so that the expectation for the simulation is growing further.
The electric loss of the electric equipment using the magnetic material includes a copper loss caused by a coil (an eddy current loss caused by a coil), a classic eddy current loss caused by the magnetic material, a hysteresis loss resulting from the hysteresis of the magnetic material, and an abnormal eddy current loss. In order to calculate the efficiency of the electric equipment, it is necessary to obtain such a loss correctly. By the progress of the technology of driving the electric equipment in recent years, the case where a high-frequency magnetic field (e.g. a magnetic field of KHz order) is applied to the magnetic material increases, compared with the past. In such a situation, the loss in the magnetic material tends to increase and the exact estimate of the loss in the magnetic material becomes an important item for optimization of the structure and the material of the electric equipment.
In the finite element method employed by the simulation of the electric equipment, a magnetic material model is a simple model which defines only a relationship between a magnetic permeability and a magnetic flux density, as illustrated in FIG. 1. Consequently, the magnetic material model of FIG. 1 cannot express a hysteresis curve of the magnetic material, so that there is a problem that the hysteresis loss and the abnormal eddy current loss which occur in the magnetic material are uncomputable.
For such a problem, a method for calculating the hysteresis loss and the abnormal eddy current loss by the formulas decided analytically is employed in the present simulation. For example, according to Non-patent Document 1 (“Katsumi Yamazaki, Yousuke Isoda, “Iron Loss and Magnet Eddy Current Loss Analysis of IPM Motors with Concentrates Windings”, IEEJ (Institute of Electrical Engineers of Japan) Trans. 1A, Vol. 128, No. 5, 2008”), the hysteresis loss Wh and the abnormal eddy current loss We when the high-frequency magnetic field is applied to the magnetic material model are calculated by the following analysis formulas (1) and (2), respectively. In this method, since “Kh” and “Ke” in the formulas are factors calculated from catalog data of the magnetic material, the factors are different from values in an actual operating state of the electric equipment, and hence it is difficult to exactly calculate the hysteresis loss and the abnormal eddy current loss.
                              W          h                =                              ∑            n                    ⁢                      {                                          ∫                iron                                                                              ⁢                                                K                  h                                ⁢                                                      D                    ⁡                                          (                      nf                      )                                                        2                                ⁢                                  (                                                            B                                              r                        ,                        n                                            2                                        +                                          B                                              θ                        ,                        n                                            2                                                        )                                ⁢                                  ⅆ                  v                                                      }                                              (        1        )                                          W          e                =                              ∑            n                    ⁢                      {                                          ∫                iron                                                                              ⁢                                                K                  e                                ⁢                                                      D                    ⁡                                          (                      nf                      )                                                        2                                ⁢                                  (                                                            B                                              r                        ,                        n                                            2                                        +                                          B                                              0                        ,                        n                                            2                                                        )                                ⁢                                  ⅆ                  v                                                      }                                              (        2        )            
Although Non-patent Document 2 (“Tetsuji Matsuo, Yasushi Terada, Masaaki Shimasaki, “Representation of minor hysteresis loops of a silicon steel sheet using stop and play models”, http://www.sciencedirect.com, Physica B, Volume 372, Issues 1-2, 1 Feb. 2006, Pages 25-29”) studies the calculation of a hysteresis loop of the magnetic material by an analytical method called “Stop and Play Models”, the method has not been used for actual analysis yet.
There is known a calculation method by micromagnetics of Non-patent Document 3 (“William Fuller Brown, Jr., “Thermal Fluctuations of a Single-Domain Particle”, Physical Review, Volume 130, Number 5, 1 Jun. 1963”) as a simulation method treating the magnetic domain structure and the magnetic domain wall of the magnetic material. Although Non-patent Document 4 (“Tetsuji Matsuo, Yuya Yamazaki, Takeshi Iwashita, “A Study of Demagnetizing Field in Micromagnetic Simulation under Periodic Boundary Condition”, The Papers of Technical Meeting, IEE Japan, MAG-10-17, SA10-17, RM10-17, January 2010”) studies the hysteresis loop of the micromagnetics, the hysteresis loop is not applied to actual analysis.